TOPICS: Blood clot, deep veins, embolize, Virchow's triad, stasis of blood flow, hypercoagulability, endothelial injury, collagen, factor V leiden, protein C or S deficiency, antithrombin III deficiency, oral contraceptives, obesity, pregnancy, smoking, cancer, nephrotic syndrome, asymmetrical swelling of leg, erythema, Homan's sign, asymmetric calf diameter, D-dimer, ultrasound with compression, doppler, sequential compression devices, ambulation, enoxaparin, unfractionated heparin, oral anticoagulants, warfarin